1. Field of the Invention
This invention relates to an apparatus for raising and lowering a mower unit vertically movably connected to a lawn tractor, the apparatus including a control lever for raising and lowering the mower unit, and an assist mechanism for assisting operations of the control lever to raise and lower the mower unit.
2. Description of the Related Art
In this type of conventional apparatus for raising and lowering a mower unit connected to a lawn tractor, an upward assisting force is constantly applied to the mower unit by means of coil springs or the like to reduce an upward operating force.
In the prior art noted above, the upward assisting force may be increased to minimize the upward operating force. Then, the mower unit can easily be raised since the increased upward assisting force constantly acts on the mower unit. For example, during a grass cutting operation on a rugged ground with the mower unit lowered, the mower unit could rise easily to a large extent only by a minor upward thrust applied thereto. Thus, the mower unit tends to move up and down unstably during an operation on a rugged ground, resulting in non-uniform grass cutting heights.
If the upward assisting force is reduced to avoid the above inconvenience, a strong upward operating force will be required which lowers the efficiency of raising the mower unit.